CHEM 309 Study Guide - Midterm Guide: Electron Affinity, Electron Configuration, Sulfur
Document Summary
H- has the largest radii because it has only 1 proton with 2 electrons. It has low nuclear charge because it only has 1 proton, whereas he and li+ have 2 and 3 protons, respectively. Furthermore, it has the same number of electrons as the other atoms but with less nuclear charge, therefore it has a weaker pull on the electrons and the radii will be bigger. From left to right of the periodic table, more electrons are added to the atom, and their repulsion keeps orbitals large. The combined effects of increasing electrons and nuclear charge leads to a gradual decrease in atom size when going left to right on periodic table: phosphorus has lower electron affinity because there are already 3 electrons in its. So adding another electron would require overcoming a small energy barrier of electron repulsion. ___ ___ ___ so an electron can be added in the 3rd p orbital.
